Tissue-removing catheter

ABSTRACT

A tissue-removing catheter for removing tissue in a body lumen includes an elongate body having an axis and proximal and distal end portions spaced apart from one another along the axis. The elongate body is sized and shaped to be received in the body lumen. A handle is mounted to the proximal end portion of the elongate body and operable to cause rotation of the elongate body. A tissue-removing element is mounted on the distal end portion of the elongate body. An inner liner is received within the elongate body and coupled to the handle at a proximal end of the inner liner. A sensor is arranged with respect to the elongate body and inner liner and is configured to detect wear of the inner liner caused by the elongate body contacting the inner liner during use.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of, and priority to, U.S.Provisional Application Ser. No. 62/500,867, which was filed May 3,2017, and U.S. Patent Application Ser. No. 62/500,879, which was filedMay 3, 2017, each of which is incorporated herein by reference in itsentirety for all purposes.

FIELD

The present disclosure generally relates to a tissue-removing catheter,and more particular, to an isolation liner wear sensor for atissue-removing catheter.

BACKGROUND

Tissue-removing catheters are used to remove unwanted tissue in bodylumens. As an example, atherectomy catheters are used to remove materialfrom a blood vessel to open the blood vessel and improve blood flowthrough the vessel. This process can be used to prepare lesions within apatient's coronary artery to facilitate percutaneous coronaryangioplasty (PTCA) or stent delivery in patients with severely calcifiedcoronary artery lesions. Atherectomy catheters typically employ arotating element which is used to abrade or otherwise break up theunwanted tissue.

SUMMARY

In one aspect, a tissue-removing catheter for removing tissue in a bodylumen generally comprises an elongate body having an axis and proximaland distal end portions spaced apart from one another along the axis.The elongate body is sized and shaped to be received in the body lumen.A handle is mounted to the proximal end portion of the elongate body andoperable to cause rotation of the elongate body. A tissue-removingelement is mounted on the distal end portion of the elongate body. Thetissue-removing element is configured to remove the tissue as thetissue-removing element is rotated by the elongate body within the bodylumen. An inner liner is received within the elongate body and coupledto the handle at a proximal end of the inner liner. The inner linerdefines a guidewire lumen. A sensor is arranged with respect to theelongate body and inner liner and is configured to detect wear of theinner liner caused by the elongate body contacting the inner linerduring use.

In another aspect, a tissue-removing catheter for removing tissue in abody lumen generally comprises an elongate body having an axis andproximal and distal end portions spaced apart from one another along theaxis. The elongate body is sized and shaped to be received in the bodylumen. A tissue-removing element is mounted on the distal end portion ofthe elongate body. The tissue-removing element is configured to removethe tissue as the tissue-removing element is rotated by the elongatebody within the body lumen. An inner liner is received within theelongate body. The inner liner defines a guidewire lumen. A sensor isarranged with respect to the elongate body and inner liner and isconfigured to detect wear of the inner liner caused by the elongate bodycontacting the inner liner during use.

In still another aspect, a method of removing tissue in a body lumengenerally comprises advancing a tissue-removing catheter over aguidewire in the body lumen to position a distal end of the catheteradjacent the tissue and a proximal end portion of the catheter outsideof the body lumen. The catheter comprises an elongate body, a tissueremoving element mounted on a distal end portion of the elongate body,and an inner liner disposed within the elongate body. The inner linerdefines a guidewire lumen in which the guidewire is disposed during theadvancement of the catheter. The method further comprises rotating theelongate body and tissue-removing element of the catheter to remove thetissue. And detecting wear of the inner liner caused by the elongatebody contacting the inner liner during use.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation of a catheter of the present disclosure;

FIG. 1A is a schematic illustration of a liner wear sensor circuit ofthe catheter;

FIG. 2 is an enlarged elevation of a distal end portion of the catheter;

FIG. 3 is an enlarged elevation of a proximal end portion of thecatheter;

FIG. 4 is an enlarged fragmentary longitudinal cross section of thedistal end portion of the catheter in FIG. 2;

FIG. 5 is a cross section taken through line 5-5 in FIG. 2;

FIG. 6 is a fragmentary elevation of an isolation liner of the catheterwith portions broken away to show internal details;

FIG. 7 is an enlarged elevation of a distal end portion of the cathetershowing an atraumatic tip on an inner liner;

FIG. 8 is an enlarged elevation of a distal end portion of the cathetershowing a tapered tip on an inner liner; and

FIG. 9 is an enlarged longitudinal cross section of a tissue-removingelement of the catheter.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

DETAILED DESCRIPTION

Referring to the drawings, and in particular FIG. 1, a rotationaltissue-removing catheter for removing tissue in a body lumen isgenerally indicated at reference number 10. The illustrated catheter 10is a rotational atherectomy device suitable for removing (e.g.,abrading, cutting, excising, ablating, etc.) occlusive tissue (e.g.,embolic tissue, plaque tissue, atheroma, thrombolytic tissue, stenotictissue, hyperplastic tissue, neoplastic tissue, etc.) from a vessel wall(e.g., coronary arterial wall, etc.). The catheter 10 may be used tofacilitate percutaneous coronary angioplasty (PTCA) or the subsequentdelivery of a stent. Features of the disclosed embodiments may also besuitable for treating chronic total occlusion (CTO) of blood vessels,and stenoses of other body lumens and other hyperplastic and neoplasticconditions in other body lumens, such as the ureter, the biliary duct,respiratory passages, the pancreatic duct, the lymphatic duct, and thelike. Neoplastic cell growth will often occur as a result of a tumorsurrounding and intruding into a body lumen. Removal of such materialcan thus be beneficial to maintain patency of the body lumen.

The catheter 10 is sized for being received in a blood vessel of asubject. Thus, the catheter 10 may have a maximum size of 3, 4, 5, 6, 7,8, 9, 10, or 12 French (1, 1.3, 1.7, 2, 2.3, 2.7, 3, 3.3, or 4 mm) andmay have a working length of 20, 30, 40, 60, 80, 100, 120, 150, 180 or210 cm depending of the body lumen. While the remaining discussion isdirected toward a catheter for removing tissue in blood vessels, it willbe appreciated that the teachings of the present disclosure also applyto other types of tissue-removing catheters, including, but not limitedto, catheters for penetrating and/or removing tissue from a variety ofocclusive, stenotic, or hyperplastic material in a variety of bodylumens.

Referring to FIGS. 1 and 2, the catheter 10 comprises an elongate outerlayer 12 (broadly, an elongate body) disposed around an elongate innerliner 14. The outer layer 12 and inner liner 14 extend along alongitudinal axis LA of the catheter from a proximal end portion 16 to adistal end portion 18 of the catheter. A tissue-removing element 20 isdisposed on a distal end of the outer layer 12 and is configured forrotation to remove tissue from a body lumen as will be explained ingreater detail below. A sheath 22 (FIG. 1) is disposed around the outerlayer 12. The outer layer 12 and the inner liner 14 are both configuredto translate relative to the sheath 22. The outer layer 12 and innerliner 14 are also configured to translate relative to each other. Thecatheter 10 is sized and shaped for insertion into a body lumen of asubject. The sheath 22 isolates the body lumen from at least a portionof the outer layer 12 and inner liner 14. The inner liner 14 defines aguidewire lumen 24 (FIG. 5) for slidably receiving a guidewire 26therein so that the catheter 10 can be advanced through the body lumenby traveling along the guidewire. The guidewire can be a standard 0.014inch outer diameter, 300 cm length guidewire. In certain embodiments,the inner liner 14 may have a lubricious inner surface for sliding overthe guidewire 26 (e.g., a lubricious surface may be provided by alubricious polymer layer or a lubricious coating). In the illustratedembodiment, the guidewire lumen 24 extends from the proximal end portion16 through the distal end portion 18 of the catheter 10 such that theguidewire 26 is extendable along an entire working length of thecatheter 10. In one embodiment, the overall working length of thecatheter 10 may be between about 135 cm (53 inches) and about 142 cm (56inches).

The catheter 10 further comprises a handle 40 secured at the proximalend portion 16 of the catheter. The handle 40 supports an actuator 42(e.g., a lever, a button, a dial, a switch, or other device) configuredfor selectively actuating a motor 43 disposed in the handle to driverotation of the outer layer 12, and tissue-removing element 20 mountedat the distal end of the outer layer. The motor 43 is coupled to theouter layer 12 by a gear assembly 44 and drive 48 supported by thehandle 40. A slide or advancer 45 is positioned on the handle 40 andoperatively coupled to the outer layer 12 for movement of the outerlayer relative to the handle to advance and retract the outer layer andtissue-removing element 20. The handle 40 defines a slot (not shown)which limits the movement of the slide 45 relative to the handle. Thus,the length of the slot determines the amount of relative movementbetween the outer layer 12 and the handle 40. A perfusion port 46 may bedisposed at the proximal end 16 of the catheter 10. The port 46communicates with a space between the sheath 22 and the outer layer 12for delivering fluid (e.g., saline) to cool the rotating outer layerduring use. A proximal port 47 allows for passage of the guidewire 26and inner liner 14 through the proximal end of the handle 40. Aguidewire lock 49 (FIG. 1A) may be provided on the handle 40 to lock theguidewire 26 in place relative to the handle.

A controller 50 may be provided in the handle 40. The controller 50 maybe programmed to detect a signal indicating that contact between theguidewire 26 and the outer layer 12 has occurred. Such contact may be aresult of a portion of the inner liner 14 wearing away during use. Thecontroller 50 may be configured to produce an alarm signal (e.g.,audible sound, visual indication, etc.) when guidewire to outer layercontact is detected. The liner wear detection may be accomplished bycreating one of a positive and a negative terminal in the outer layer12, and creating the other of the positive and negative terminal in theguidewire 26. The inner liner 14 is disposed between the guidewire 26and the outer layer 12. Therefore, if the inner liner 14 is intact, theliner will space the guidewire 26 and outer layer 12, and thus space theterminal associated with the guidewire from the terminal associated withthe outer layer, preventing the circuit from being completed. However,in the result of any wear in the inner liner 14 which causes thematerial of the inner liner to degrade to such an extent that theguidewire 26 is able to contact the outer layer 12 at the worn area ofthe inner liner, then the metal-to-metal contact of the guidewire andouter layer will place the terminals in electrical contact and completethe liner wear circuit. The controller 50 is in electrical communicationwith the terminals such that the controller can recognize the completedcircuit indicating that at least some portion of the liner has wornaway. The controller 50 may then signal an alarm component 57 to signalthat the liner wear has occurred. Alternatively, the alarm component 57can be part of the electric circuit as shown in FIG. 1A such that whenthe circuit is closed the alarm is automatically signaled.

Referring to FIGS. 1 and 1A, the guidewire lock 49 may include aterminal 59, for example a negative terminal, for being associated withthe guidewire 26. As such, when the guidewire lock 49 is engaged to lockthe guidewire 26 in place, the guidewire lock comes into contact withthe guidewire so that the terminal 59 in the guidewire lock is also inelectrical contact with the guidewire. A drive key 53 on a drive shaft55 of the drive 48 may also include a terminal 61, for example apositive terminal, for being associated with the outer layer 12. Thedrive key 53 is in contact with the outer layer 12 and connects theouter layer to drive shaft 55 and motor 43. Therefore, during normaloperation of the catheter 10, the inner liner 14 spaces and isolates theguidewire 26 from the outer layer 12 preventing the terminals fromcoming into electrical contact with each other. This creates an opencircuit where current does not flow between the terminals. However, ifthe inner liner 14 becomes worn to the point where the guidewire 26 isable to contact the outer layer 12, the metal-to-metal contact betweenthe components will place the terminals in electrical communicationwhere current flows between the two terminals closing the circuit. Withthe circuit closed, the alarm component 57 alerts the user of the linerworn condition.

Alternatively, a connector (not shown) including a terminal can betattached to the guidewire lock 49. For example, the connector may attachto the proximal end of the handle 40 over the guidewire lock 49 forplacing the terminal in the connector in contact with the guidewire 26.

In some embodiments, an isolating coating may be applied to theguidewire 26 in addition to or in place of the inner liner 14. The linerwear circuit may also be used to indicate that the guidewire coating hasworn away. In this embodiment, one of the positive and negativeterminals is associated with the guidewire 26 and the other of thepositive and negative terminals is associated with the outer layer 12,as described above.

Additionally or alternatively, one of a positive and a negative terminalmay be associated with the inner liner 14 and the other of the positiveand negative terminal may be associated with the outer layer 12. Forexample, the terminal associated with the inner liner 14 may be attachedto an interior or inner surface of the liner such as intermediate layer62, and the terminal associated with the outer layer 12 may be attachedto the drive shaft 55 and drive key 53. In this embodiment, frictionfrom the outer layer 12 on the exterior surface of the inner liner 14may wear away the liner exposing an interior or inner surface of theliner creating the metal-to-metal contact for completing the liner wearcircuit.

It is understood that other suitable actuators, including but notlimited to touchscreen actuators, wireless control actuators, automatedactuators directed by a controller, etc., may be suitable to selectivelyactuate the motor in other embodiments. In some embodiments, a powersupply may come from a battery 63 contained within the handle 40. Thebattery 63 can provide the current source for the liner wear circuit. Inother embodiments, the power supply may come from an external source.

Referring to FIGS. 1 and 3, the outer sheath 22 comprises a tubularsleeve configured to isolate and protect a subject's arterial tissuewithin a body lumen from the rotating outer layer 12. The sheath 22 isfixed to the handle 40 at a proximal end of the sheath and does notrotate. A hub 52 mounted on the proximal end of the sheath 22 attachesthe sheath to the handle 40. The hub 52 includes a locking feature 54(e.g., threaded luer lock) for engaging the handle 40 to attach thesheath 22 to the handle. The sheath 22 provides a partial enclosure forthe outer layer 12 and inner liner 14 to move within the sheath. Theinner diameter of the sheath 22 is sized to provide clearance for theouter layer 12. The space between the sheath 22 and the outer layer 12allows for the outer layer to rotate within the sheath and provides anarea for saline perfusion between the sheath and outer layer. The outerdiameter of the sheath 22 is sized to provide clearance with an innerdiameter of a guide catheter (not shown) for delivering the catheter 10to the desired location in the body lumen. A strain relief 56 isprovided at the proximal end of the sheath 22 to alleviate tensionapplied to the proximal end of the sheath 22 as the sheath is bentduring use of the catheter 10. In one embodiment, the sheath 22 has aninner diameter of about 0.050 inches (1.27 mm), an outer diameter ofabout 0.055 inches (1.4 mm), and a length of about 1500 mm (59 inches).The sheath 22 can have other dimensions without departing from the scopeof the disclosure. In one embodiment, the outer sheath 22 is made fromPolytetrafluorethylene (PTFE). Alternatively, the outer sheath 22 maycomprise a multi-layer construction. For example, the outer sheath 22may comprises an inner layer of perfluoroalkox (PFA), a middle braidedwire layer, and an outer layer of Pebax.

Referring to FIGS. 1, 2, 4, and 5, the outer layer 12 may comprise atubular stainless steel coil configured to transfer rotation and torquefrom the motor 43 to the tissue-removing element 20. Configuring theouter layer 12 as a coiled structure provides the outer layer with aflexibility that facilitates delivery of the catheter 10 through thebody lumen. Also, the coil configuration allows for the rotation andtorque of the outer layer 12 to be applied to the tissue-removingelement 20 when the catheter 10 is traversed across a curved path. Thestiffness of the outer layer 12 also impacts the ease at which the coilis traversed through the body lumen as well as the coil's ability toeffectively transfer torque to the tissue-removing element 20. In oneembodiment, the outer layer 12 is relatively stiff such that axialcompression and extension of the coil is minimized during movement ofthe catheter 10 through a body lumen. The coil configuration of theouter layer 12 is also configured to expand its inner diameter when thecoil is rotated so that the outer layer remains spaced from the innerliner 14 during operation of the catheter 10. In one embodiment, theouter layer 12 has an inner diameter of about 0.023 inches (0.6 mm) andan outer diameter of about 0.035 inches (0.9 mm). The outer layer 12 mayhave a single layer construction. For example, the outer layer maycomprise a 7 filar (i.e., wire) coil with a lay angle of about 30degrees. Alternatively, the outer layer 12 could be configured frommultiple layers without departing from the scope of the disclosure. Forexample, the outer layer 12 may comprise a base coil layer and a jacket(e.g., Tecothane™) disposed over the base layer. In one embodiment, theouter layer comprises a 15 filar coil with a lay angle of about 45degrees. The Tecothane™ jacket may be disposed over the coil.Alternatively, the outer layer 12 may comprise a dual coil layerconfiguration which also includes an additional jacket layer over thetwo coil layers. For example, the outer layer may comprise an inner coillayer comprising a 15 filar coil with a lay angle of about 45 degrees,and an outer coil layer comprising a 19 filar coil with a lay angle ofabout 10 degrees. Outer layer having other configurations are alsoenvisioned.

Referring to FIGS. 1, 2, and 4-6, the inner liner 14 comprises amultiple layer tubular body configured to isolate the guidewire 26 fromthe outer layer 12 and tissue-removing element 20. The inner liner 14 isextendable through the handle 40 from a position proximal of the handleto a position distal of the handle. In one embodiment, the inner liner14 is coupled to the handle 40 but is not fixedly attached to the handle40 to allow translation of the inner liner relative to the handle. Inthis embodiment, rotation of the inner liner 14 is not prevented.However, the clearance between the inner liner 14 and the outer layer 12prevents any rotation of the inner liner caused by the rotation of theouter layer. In this embodiment, both the inner liner 14 and outer layer12 are permitted to translate relative to the handle 40. Allowing thisco-translation of the inner liner 14 and outer layer 12 minimizescompression and extension of the coiled outer layer 14 when force isapplied to the outer layer to move the outer layer within the bodylumen. In another embodiment, the inner liner 14 may be fixedly attachedto the handle 40 to prevent relative movement between the inner linerand the handle. Thus, in this embodiment, the inner liner 14 remainsstationary and is prevented from translating relative to the handle 40.Additionally, all rotation of the inner liner 14 is prevented. In thisembodiment, the outer layer 12 translates over the stationary innerliner 14.

The inner liner 14 has an inner diameter that is sized to pass theguidewire 26. The inner liner 14 protects the guide wire from beingdamaged by the rotation of the outer layer 12 by isolating the guidewirefrom the rotatable outer layer. The inner liner 14 also extends past thetissue-removing element 20 to protect the guidewire 26 from the rotatingtissue-removing element. Thus, the inner liner 14 is configured toprevent any contact between the guidewire 26 and the rotating componentsof the catheter 10. Therefore, any metal-to-metal engagement iseliminated by the inner liner 14. This isolation of the outer layer 12and tissue-removing element 20 from the guidewire 26 also ensures thatthe rotation of the outer layer and tissue-removing element is nottransferred or transmitted to the guidewire. As a result, a standardguidewire 26 can be used with the catheter 10 because the guidewire doesnot have to be configured to withstand the torsional effects of therotating components. Additionally, by extending through thetissue-removing element 20 and past the distal end of thetissue-removing element, the inner liner 14 stabilizes thetissue-removing element by providing a centering axis for rotation ofthe tissue-removing element about the inner liner.

In the illustrated embodiment, the inner liner 14 comprises an innerPTFE layer 60 an intermediate braided layer 62 comprised of stainlesssteel, and an outer layer 64 of polyimide. The PTFE inner layer 60provides the inner liner 14 with a lubricous interior which aids in thepassing of the guidewire 26 though the inner liner. The braidedstainless steel intermediate layer 62 provides rigidity and strength tothe inner liner 14 so that the liner can withstand the torsional forcesexerted on the inner liner by the outer layer 12. In one embodiment, theintermediate layer 62 is formed from 304 stainless steel. The outerpolyimide layer 64 provides wear resistance as well as having alubricous quality which reduces friction between the inner liner 14 andthe outer layer 12. Additionally, a lubricious film, such as silicone,can be added to the inner liner 14 to reduce friction between the innerliner and the outer layer 12. In one embodiment, the inner liner 14 hasan inner diameter ID of about 0.016 inches (0.4 mm), an outer diameterOD of about 0.019 inches (0.5 mm), and a length of about 59 inches (1500mm). The inner diameter ID of the inner liner 14 provide clearance forthe standard 0.014 inch guidewire 26. The outer diameter OD of the innerliner 14 provides clearance for the outer layer 12 and tissue-removingelement 20. Having a space between the inner liner 14 and the outerlayer 12 reduces friction between the two components as well as allowsfor saline perfusion between the components.

In the illustrated embodiment, a marker band 66 is provided on anexterior surface of the distal end of the inner liner 14. The markerband 66 configures the tip of the inner liner 14 to be fluoroscopicallyvisible which allow a physician to verify the position of the linerduring a medical procedure. In this embodiment, the distal end of theinner liner 14 may be laser cut to provide a low profile tip. In oneembodiment, the marker band 66 comprises a strip of platinum iridium.

It is further envisioned that the distal end of the inner liner 14 canhave other constructions without departing from the scope of thedisclosure. For example, an atraumatic tip 68 may be attached to thedistal end of the inner liner 14 (FIG. 7). The atraumatic tip 68provides a soft, low profile distal end to facilitate delivery of theinner liner 14 through the body lumen without causing trauma. Theatraumatic tip 68 may have a maximum outer diameter of about 0.02 inches(0.6 mm). Other sizes of the atraumatic tip are also envisioned. Inanother embodiment, a tapered tip 70 may be attached to the distal endof the inner liner 14 (FIG. 8). The tapered tip 70 may be formed from alayer of material configured to protect the distal end of the innerliner 14.

Referring to FIGS. 1, 2, and 9, the tissue-removing element 20 extendsalong the longitudinal axis LA from a proximal end adjacent the distalend portion of the outer layer 12 to an opposite distal end. Thetissue-removing element 20 is operatively connected to the motor 43 forbeing rotated by the motor. When the catheter 10 is inserted into thebody lumen and the motor 43 is rotating the tissue-removing element 20,the tissue-removing element is configured to remove occlusive tissue inthe body lumen to separate the tissue from the wall of the body lumen.Any suitable tissue-removing element for removing tissue in the bodylumen as it is rotated may be used in one or more embodiments. In oneembodiment, the tissue-removing element 20 comprises an abrasive burrconfigured to abrade tissue in the body lumen when the motor 43 rotatesthe abrasive burr. The abrasive burr 20 may have an abrasive outersurface formed, for example, by a diamond grit coating, surface etching,or the like. In one embodiment, the tissue-removing element comprises astainless steel spheroid body with an exterior surface including 5 μm ofexposed diamond crystals. The tissue-removing element 20 may also beradiopaque to allow the tissue-removing element to be visible underfluoroscopy. In other embodiments, the tissue-removing element cancomprise one or more cutting elements having smooth or serrated cuttingedges, a macerator, a thrombectomy wire, etc.

A cavity 72 extends longitudinally through the tissue-removing element20 such that the tissue-removing element defines openings at itsproximal and distal ends. The cavity 72 receives a portion of the outerlayer 12 for mounting the tissue-removing element 20 to the outer layer.The cavity 72 includes a first diameter portion 74 extending from theproximal end of the tissue-removing element 20, a tapered diameterportion 76 extending from the first diameter portion toward the distalend of the tissue-removing element, and a second diameter portion 78extending from the tapered diameter portion to the distal end of thetissue-removing element. The diameters of the first and second diameterportions 74, 78 are constant along their lengths. In the illustratedembodiment, a diameter D1 of the first diameter portion 74 is largerthan a diameter D2 of the second diameter portion 78. In one embodiment,the diameter D1 of the first diameter portion 74 is about 0.035 inches(0.9 mm), and the diameter D2 of the second diameter portion 78 is about0.022 inches (0.56 mm). The tapered diameter portion 76 provides atransition between the first and second diameter portions 74, 78. Theouter layer 12 is received in the first diameter portion 74 and a distalend of the outer layer abuts the tapered diameter portion 76. Thetissue-removing element 20 can be fixedly attached to the distal end ofthe outer layer 12 by any suitable means. In one embodiment an adhesivebonds the tissue-removing element 20 to the outer layer 12. The innerliner 14 extends through the outer layer 12 and the second diameterportion 78 of the tissue-removing element 20. The second diameterportion 78 is sized to pass the inner liner 14 with a small clearance.The inner diameter D2 provides clearance between the tissue-removingelement 20 and inner liner 14 to reduce friction between the componentsand allow a space for saline perfusion. Accordingly, the tissue-removingelement 20 is shaped and arranged to extend around at least a portion ofthe outer layer 12 and inner liner 14 and thus provides a relativelycompact assembly for abrading tissue at the distal end portion of thecatheter 10.

The exterior surface of the tissue-removing element 20 includes aproximal segment 80, a middle segment 82, and a distal segment 84. Adiameter of the proximal segment 80 increases from the proximal end ofthe tissue-removing element 20 to the middle segment 82. The middlesegment has a constant diameter and extends from the proximal segment 80to the distal segment 84. The diameter of the distal segment 84 tapersfrom the middle segment 82 to the distal end of the tissue-removingelement 20. The tapered distal segment 84 provides the tissue-removingelement 20 with a general wedge shape configuration for wedging apartconstricted tissue passages as it simultaneously opens the passage byremoving tissue using the abrasive action of the tissue-removingelement. The distal end of the tissue-removing element 20 is alsorounded to provide the tissue-removing element with a blunt distal end.

Referring to FIGS. 1 and 2, to remove tissue in the body lumen of asubject, a practitioner inserts the guidewire 26 into the body lumen ofthe subject, to a location distal of the tissue that is to be removed.Subsequently, the practitioner inserts the proximal end portion of theguidewire 26 through the guidewire lumen 24 of the inner liner 14 andthrough the handle 40 so that the guidewire extends through the proximalport 47 in the handle. The inner liner 14 may also extend through thehandle 40 and out the proximal port 47. With the catheter 10 loaded ontothe guidewire 26, the practitioner advances the catheter along theguidewire until the tissue-removing element 20 is positioned proximaland adjacent the tissue. When the tissue-removing element 20 ispositioned proximal and adjacent the tissue, the practitioner actuatesthe motor 43 using the actuator 42 to rotate the outer layer 12 and thetissue-removing element mounted on the outer layer. The tissue-removingelement 20 abrades (or otherwise removes) the tissue in the body lumenas it rotates. While the tissue-removing element 20 is rotating, thepractitioner may selectively move the outer layer 12 and inner liner 14distally along the guidewire 26 to abrade the tissue and, for example,increase the size of the passage through the body lumen. Thepractitioner may also move the outer layer 12 and inner liner 14proximally along the guidewire 26, and may repetitively move thecomponents in distal and proximal directions to obtain a back-and-forthmotion of the tissue-removing element 20 across the tissue. During theabrading process, the inner liner 14 isolates the guidewire 26 from therotating outer layer 12 and tissue-removing element 20 to protect theguidewire from being damaged by the rotating components. As such, theinner liner 14 is configured to withstand the torsional and frictionaleffects of the rotating outer layer 12 and tissue-removing element 20without transferring those effects to the guidewire 26. When thepractitioner is finished using the catheter 10, the catheter can bewithdrawn from the body lumen and unloaded from the guidewire 26 bysliding the catheter proximally along the guidewire. The guidewire 26used for the abrading process may remain in the body lumen for use in asubsequent procedure.

When introducing elements of the present invention or the one or moreembodiment(s) thereof, the articles “a”, “an”, “the” and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

As various changes could be made in the above apparatuses, systems, andmethods without departing from the scope of the invention, it isintended that all matter contained in the above description and shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

What is claimed is:
 1. A tissue-removing catheter for removing tissue ina body lumen, the tissue-removing catheter comprising: an elongate bodyhaving an axis and proximal and distal end portions spaced apart fromone another along the axis, the elongate body being sized and shaped tobe received in the body lumen; a handle mounted to the proximal endportion of the elongate body and operable to cause rotation of theelongate body; a tissue-removing element mounted on the distal endportion of the elongate body, the tissue-removing element beingconfigured to remove the tissue as the tissue-removing element isrotated by the elongate body within the body lumen; an inner linerreceived within the elongate body and coupled to the handle at aproximal end of the inner liner, the inner liner defining a guidewirelumen; and a sensor arranged with respect to the elongate body and innerliner and configured to detect wear of the inner liner caused by theelongate body contacting the inner liner during use.
 2. Atissue-removing catheter as set forth in claim 1, wherein the sensorprovides an indication of at least one of when the elongate body comesinto contact with a guidewire received in the guidewire lumen of theinner liner, and when the elongate body comes into contact with aninterior portion of the inner liner.
 3. A tissue-removing catheter asset forth in claim 2, wherein the sensor comprises a first contactassociated with the elongate body and a second contact associated withthe guidewire, the first contact coming into electrical communicationwith the second contact indicating wear of the inner liner.
 4. Atissue-removing catheter as set forth in claim 3, wherein the handleincludes a motor and a drive operatively connecting the motor to theelongate body for rotating the elongate body, the first contact beingattached to the drive.
 5. A tissue-removing catheter as set forth inclaim 4, wherein the handle includes a guidewire lock configured to lockthe guidewire in place relative to the handle, the second contact beingattached to the guidewire lock.
 6. A tissue-removing catheter as setforth in claim 5, wherein the second contact is attached directly to theguidewire lock.
 7. A tissue-removing catheter as set forth in claim 5,further comprising a connector attached to the handle, wherein thesecond contact is directly attached to the connector.
 8. Atissue-removing catheter as set forth in claim 4, wherein the drivecomprises a drive shaft and a drive key connected to the drive shaft,the first contact being attached to the drive key.
 9. A tissue-removingcatheter as set forth in claim 2, wherein the sensor comprises a firstcontact associated with the elongate body and a second contactassociated with the inner liner, the first contact coming intoelectrical communication with the second contact indicating wear of theinner liner.
 10. A tissue-removing catheter as set forth in claim 1,wherein a distal end of the inner liner extend distally of thetissue-removing element.
 11. A tissue-removing catheter as set forth inclaim 1, further comprising a motor in the handle and operativelyengaging the elongate body for driving rotation of the elongate body andtissue-removing element mounted on the elongate body.
 12. Atissue-removing catheter for removing tissue in a body lumen, thetissue-removing catheter comprising: an elongate body having an axis andproximal and distal end portions spaced apart from one another along theaxis, the elongate body being sized and shaped to be received in thebody lumen; a tissue-removing element mounted on the distal end portionof the elongate body, the tissue-removing element being configured toremove the tissue as the tissue-removing element is rotated by theelongate body within the body lumen; an inner liner received within theelongate body, the inner liner defining a guidewire lumen; and a sensorarranged with respect to the elongate body and inner liner andconfigured to detect wear of the inner liner caused by the elongate bodycontacting the inner liner during use.
 13. A tissue-removing catheter asset forth in claim 12, wherein the sensor provides an indication of atleast one of when the elongate body comes into contact with a guidewirereceived in the guidewire lumen of the inner liner, and when theelongate body comes into contact with an interior portion of the innerliner.
 14. A tissue-removing catheter as set forth in claim 13, whereinthe sensor comprises a first contact associated with the elongate bodyand a second contact associated with the guidewire, the first contactcoming into electrical communication with the second contact indicatingwear of the inner liner.
 15. A tissue-removing catheter as set forth inclaim 14, further comprising a motor and a drive operatively connectingthe motor to the elongate body for rotating the elongate body, the firstcontact being attached to the drive.
 16. A tissue-removing catheter asset forth in claim 15, further comprising a guidewire lock configured tolock the guidewire in place, the second contact being attached to theguidewire lock.
 17. A tissue-removing catheter as set forth in claim 16,wherein the drive comprises a drive shaft and a drive key connected tothe drive shaft, the first contact being attached to the drive key. 18.A tissue-removing catheter as set forth in claim 13, wherein the sensorcomprises a first contact associated with the elongate body and a secondcontact associated with the inner liner, the first contact coming intoelectrical communication with the second contact indicating wear of theinner liner.